Guerrilla inmates fought police Thursday in the second day of a bloody prison battle, and the death toll rose to at least 12.
Police are trying to take over a cellblock that is controlled by imprisoned members of Sendero Luminoso (Shining Path), a Maoist guerrilla movement.
An Interior Ministry statement said 10 inmates and two policemen have died in the siege, which began before dawn Wednesday.
One policeman died from burns after prisoners poured muriatic acid on him from a cellblock roof.
Radio reports said the bodies of several more inmates and policemen had not been recovered from the besieged Miguel Castro Castro Prison in Lima's Canto Grande district.
"This could possibly last days," said an Interior Ministry spokesman.
In 1986, troops stormed two Lima prisons holding Sendero guerrillas and killed 250 inmates.
Wednesday morning, police blasted their way into the top floor of a Castro Castro cellblock controlled by 130 women accused of membership in Sendero. The women escaped through tunnels into a men's cellblock.
Tear gas and smoke billowed from blackened windows Thursday, and explosions and machine-gun fire echoed off the barren hills flanking the prison as police moved on the men's cellblock. Soldiers patrolled the nearby hills. About 500 men and women armed with dynamite, makeshift bombs and small firearms have barricaded themselves in the cellblock, Interior Ministry sources said.
Late Thursday, police cut off water and electricity to the cellblock.
The prison siege followed a televised address Tuesday by President Alberto Fujimori, who announced a decree increasing sentences to life imprisonment for guerrilla leaders and 30 years for guerrilla assassination squads. Fujimori, who seized power in a military-backed move April 5, announced earlier that Sendero members would be moved to another prison.